Contents of the BIOC5_TX.TXT file

PREVIOUS INSTALLMENTS OF THIS SERIES WERE FOCUSED ON TELEPHONY FROM A NETWORKPOINT-OF-VIEW. PART V WILL DEAL WITH TELEPHONE ELECTRONICS FOCUSINGPRIMARILY ON THE SUBSCRIBER'S TELEPHONE. HEREINAFTER SIMPLY REFERRED TO AS "FONE."

WIRING:-------

ASSUMING A STANDARD ONE-LINE FONE, THERE ARE USUALLY 4 WIRES THAT LEAD OUT OFTHE FONE SET. THESE ARE STANDARDLY COLORED RED, CREEN, YELLOW, & BLACK. THERED & GREEN SIRES ARE THE TWO THAT ARE ACTUALLY HOOKED UP TO YOUR CO. THEYELLOW WIRE IS SOMETIMES USED TO RING DIFFERENT FONES ON A PARTY LINE (IE,ONE #, SEVERAL FAMILIES--FOUND PRIMARILY IN RURAL AREAS WHERE THEY PAY LESSFOR THE SERVICE AND THEY DON'T USE THE FONE AS MUCH); OTHERWISE, THE YELLOWIS USUALLY JUST IGNORED. ON SOME TWO-LINE FONES, THE RED & GREEN WIRES AREUSED FOR THE FIRST FONE # AND THE YELLOW & BLACK ARE USED FOR THE SECOND LINE. IN THIS CASE THERE MUST BE AN INTERNAL OR EXTERNAL DEVICE THAT SWITCHESBETWEEN THE TWO LINES AND PROVIDES A HOLD FUNCTION. (SUCH AS RADIO SHACK'SOUTRAGEOUSLY PRICED 2 LINE & HOLD MODULE9.

IN TELEPHONY, THE RED & GREEN WIRES ARE OFTEN REFERRED TO AS TIP (T) & RING (R). THE TIP IS USUALLY THE MORE POSITIVE OF THE TWO WIRES. THIS NAMINGGOES BACK TO THE OLD OPERATOR CORD BOARDS WHERE ONE OF THE WIRES WAS THE TIPOF THE PLUG AND THE OTHER WAS THE RING (OF THE BARREL).

A ROTARY FONE (AKA DIAL OR PULSE) WILL WORK FINE REGARDLESS WHETHER THE RED (OR GREEN) WIRE IS CONNECTED THE TIP(+) OR RING(-). A TOUCH-TONE (TM) FONEIS A DIFFERENT STORY, THOUGH. IT WILL NOT WORK EXCEPT IF THE TIP(+) IS THEGREEN WIRE. [ALTHOUGH, SOME OF THE MORE EXPENSIVE DTMF FONES DO HAVE ARECTIFIER BRIDGE WHICH COMPENSATES FOR POLARITY REVERSAL.] THIS I WHY UNDERCERTAIN (NON-DIGITAL) SWITCHILG EQUIPMENT YOU CAN REVERSE THE RED & GREENWIRES ON A TOUCH-TONE FONE AND RECEIVE FREE DTMF SERVICE. EVEN THOUGH IT WON'T BREAK DIAL TONE, REVERSING THE WIRES ON A ROTARY LINE ON A DIGITAL SWITCHWILL CAUSE THE TONES TO BE GENERARTED.

VOLTAGES, ETC.--------------

WHEN YOUR TELEPHONE IS ON-HOOK (IE, HUNG UP) THERE IS APPROXIMATELY 48 VOLTSOF DC CURRENT (VDC) FLOWING THROUGH THE TIP & RING. WHEN THE HANDSET OF AFONE IS LIFTED A FEW SWITCHES CLOSE WHICH CAUSE A LOOP TO BE CONNECTED (KNOWNAS THE "LOCAL LOOP") BETWEEN YOUR FONE & THE CO. ONCE THIS HAPPENS DCCURRENT IS ABLE TO FLOW THROUGH THE FONE WITH LESS RESISTANCE. THIS CAUSES ARELAY TO ENERGIZE WHICH CAUSES OTHER CO EQUIPMENT TO REALIZE THAT YOU WANTSERVICE. EVENTUALLY, YOU SHOULD END UP WITH A DIAL TONE. THIS ALSO CAUSESTHE 48 VDC TO DROP DOWN INTO THE VICINITY OF 13 VOLTS. THE RESISTANCE OF THELOOP ALSO DROPS BELOW THE 2500 OHM LEVEL.

AS OF NOW, YOU ARE PROBABLY SAYING TO YOURSELF THAT THIS IS ALL NICE ANDTECHNICAL BUT WHAT THE HELL GOOD IS THE INFORMATION. WELL, ALSO CONSIDERTHAT THIS VOLTAGE (& RESISTANCE) DROP IS HOW THE CO DETECTS THAT A FONE WASTAKEN OFF HOOK (PICKED UP). IN THIS WAY, THEY KNOW WHEN TO START BILLING THECALLING NUMBER. NOW WHAT DO YOU SUPPOSE WOULD HAPPEN IF A DEVICE SUCH AS ARESISTOR OR A ZENER DIODE WAS PLACED ON THE CALLED PARTIES LINE SO THAT THEVOLTAGE WOULD DROP JUST ENOUGH TO ALLOW TALKING BUT NOT ENOUGH TO STARTBILLING? FIRST OFF, THE CALLING PARTY WOULD NOT BE BILLED FOR THE CALL BUTCONVERSATION COULD BE PERSUED. SECONDLY, THE CO EQUIPMENT WOULD THINK THATTHE FONE JUST KEPT ON RINGING. THE TELCO CALLS THIS A "NO-NO" (TOLL FRAUD TOBE MORE SPECIFIC) WHILE PHONE PHREAKS AFFECTIONATELY CALL THIS MUTE A BLACKBOX.

THE FOLLOWING ARE INSTRUCTIONS ON HOW TO BUILD A SIMPLE BLACK BOX. OF COURSE, ANYTHING THAT PREVENTS THE VOLTAE FROM DROPPING WOULD WORK.

YOU ONE OR TWO PARTS: A SPST TOGGLE SWITCH AND A 10,000 OHM (10 K), 1/2 WATTRESISTOR. ANY ELECTRONICS STORE SHOULD STOCK THESE PARTS. NOW, CUT 2 PIECESOF WIRE (ABOUT 6 INCHES LONG) AND ATTACH ONE END OF EACH WIRE TO ONE OF THETERMINALS ON THE SWITCH. NOW TURN YOUR K500 (STANDARD DESK FONE) UPSIDE DOWNAND TAKE OFF THE COVER. LOCATE THE 2 SCREWS ON THE NETWORK BOX LABELED >F<AND >RRTOUCH ANY OTHER TERMINALS!. NOW CONNECT ONE WIRE FROM THE SWITCH TO THE RRTERMINAL. FINALLY, ATTACH THE REMAINING WIRE TO THE GREEN WIRE (DISCONNECTIT FROM ITS TERMINAL). NOW BRING THE SWITCH OUT THE REAR OF THE FONE ANDREPLACE THE COVER.

PUT THE SWITCH IN A POSITION WHERE YOU RECEIVE A DIAL TONE. MARK THISPOSITION NORMAL. MARK THE OTHER SIDE FREE.

WHEN YOUR PHRIENDS CALL (AT A PREARRANGED TIME), QUICKLY LIFT & DROP THERECEIVER AS FAST A POSSIBLE. THIS WILL STOP THE RINING (DO IT AGAIN IF ITDOESN'T) WITH OUT STARTING THE BILLING. IT IS IMPORTANT THAT YOU DO ITQUICKLY (LESS THAN ONE SECOND THEN PUT THE SWITCH IN THE FREE POSITION ANDPICK UP THE FONE. KEEP ALL CALL SHORT AND PREFERRABLY UNDER 15 MINUTES.

NOTE: IF ANYONE PICKS UP AN EXTENSION IN THE CALLED PARTIES HOUSE AND THATFONE IS NOT SET FOR FREE THEN BILLING WILL START.

NOTE #2: AN OLD WAY OF SIGNADLING A PHRIEND THAT YOU ARE ABOUT TO CALL ISMAKING A COLLECT CALL TO A NON-EXISTANT PERSON IN THE HOUSE. SINCE YOURFRIEND WILL NOT ACCEPT THE CHARGES, HE WILL KNOW THAT YOU ARE ABOUT TO CALLAND THUS PREPARE THE BLACK BOX (OR VISA VERSA).

WARNING: THE TELCO CAN DETECT BLACK BOXES IF THEY SUSPECT ONE ON YOUR LINE. THIS IS DONE DUE TO THE PRESENCE OF AC VOICE SIGNAL AT THE WRONG DC LEVEL!

NOTE: THE BLACK BOX WILL NOT WORK UNDER ESS OR OTHER SIMILAR DIGITALSWITCHES SINCE ESS DOE NOT CONNECT THE VOICE CIRCUITS UNTIL THE FONE ISPICKED UP (& BILLING STARTS). INSTEAD, ESS USES AN "ARTIFICIAL" COMPUTERGENERATED RING.

RINGING:--------

TO INFORM A SUBSCRIBER OF AN INCOMING CALL, THE TELCO SENDS 90 VOLTS (RMS) OFAC CURRENT DOWN THE LINE (AT AROUND 15 TO 60 HZ) IN STANDARD FONES, THISCAUES A METAL ARMATURE TO BE ATTRACTED ALTERNATELY BETWEEN TWO ELECTRO-MAGNETS THUS STRIKING 2 BELLS. OF COURSE, THE STANDARD BELL (PATENTED IN1878 BY TOM A. WATSON) CAN BE REPLACED BY A MORE MODERN ELECTRONIC BELL ORSIGNALING DEVICE.

ALSO, YOU CAN HAVE LIGHTS AND OTHER SIMILAR DEVICES IN LIEU OF (OR INCONJUNCTION WITH) THE BELL. A SIMPLE NEON LIGHT (WITH ITS CORRESPONDINGRESISTOR) CAN SIMPLY BE CONNECTED BETWEEN THE RED & GREEN WIRES (USUALLY L1 &L2 ON THE NETWORK BOX) SO THAT IT LIGHTS UP ON INCOMING CALLS. A REGULAR 60WATT LIGHT BULB CAN ALSO BE HOOKED UP USING A SIMPLE (120 VAC) RELAY.

ALSO INCLUDED IN THE RINGING CIRCUIT IS A CAPACITOR TO PREVENT THE DC CURRENTFROM INTERFERRING WITH THE BELL [A CAPACITOR WILL PASS AC CURRENT WHILE ITWILL PREVENT DC CURRENT FROM FLOWING (BY STORING IT)].

ANOTHER REASON THAT THE TELCO HATES BLACK BOXES IS BECUASE RINGING USES ALOTOF COMMON-CONTROL EQUIPEMET, IN THE CO, WHICH USE ALOT OF ELECTRICITY. THUSTHE RINGING GENERATORS ARE BEING TIED UP WHILE A FREE CALL IS BEING MADE. USUALLY CALLS THAT ARE ALLOWED TO RING FOR A LONG PERIOD OF TIME MAY BECONSTRUED AS SUSPICIOUS. SOME OFFICES MAY BE SET UP TO DROP A TROUBLE CARDFOR LONG PERIODS OF RINGING THEN A "NO-NO" DETECTION DEVICE MAY BE PLACED ONTHE LINE.

INCIDENTALLY, THE TERM "RING TRIP" REFERS TO THE CO PROCESS INVOLVED TO STOPTHE AC RINGING SIGNAL WHEN THE CALLING FONE GOES OFF HOOK.

NOTE: IT IS SUGGESTED THAT YOU ACTUALLY DISSECT FONES TO HELP YOU BETTERUNDERSTAND THEM. IT WILL ALSO HELP YOU TO BETTER UNDERSTAND THE CONCEPTSHERE IF YOU ACTUALLY PROVE THEM TO YOURSELF. FOR EXAMPLE, ACTUALLY TAKE THEVOLTAGE READINGS ON YOUR FONE LINE [ANY SIMPLE MULTI-TESTER (A MUST) WILL DO.] PHREAKING IS AN INTERACTIVE PROCESS NOT A PASSIVE ONE!

DIALING:--------

ON A STANDARD FONE, THERE ARE TWO COMMON TYPES OF DIALING: PULSE & DTMF. OFCOURSE, SOME PEOPLE INSIST UPON BEING DIFFERENT AND DON'T USE THE DT THUSLEAVING THEM WITH MF (MULTI FREQUNCY, AKA OPERATOR, BLUE BOX) TONES. THIS ISANOTHER "NO-NO" AND THE TELCO SECURITY GENTELMEN HAVE A SPECIAL KNACK FORDEALING WITH SUCH "PHREAKS" ON THE NETWORK.

WHEN YOU DIAL ROTARY, YOU ARE ACTUALLY RAPIDLY BREAKING & RECONNECTING (MAKING) THE LOCAL LOOP ONCE FOR EVERY DIGIT DIALED. SINCE THE PHYSICALCONNECTION MUQT BE BROKEN, YOU CANNOT DIAL IF ANOTHER EXTENSION (OF THAT #)IS OFF-HOOK. NEITHER OF THE FONES WILL BE ABLE TO DIAL PULSE UNLESS THEOTHER HANGS UP.

ANOTHER TERM OFTEN REFERRED TO IN TELEPHONE ELECTRONICS IS THE BREAK RATIO. IN THE US, THERE ARE 10 PULES PER SECOND (MAX). WHEN THE CIRCUIT IS OPENEDIT IS CALLED THE BREAK INTERVAL. WHEN IT IS CLOSED IT IS CALLED THE MAKEINTERVAL. IN THE US, THERE IS A 60 MILLISECOND (MS) BREAK PERIOD AND A 40 MSMAKE PERIOD. (60+40=100 MS = 1/10 MINUTE). THIS IS REFERRED TO AS A 60%BREAK INTERVAL. SOME OF THE MORE SOPHISTICATED ELECTRONIC FONES CAN SWITCHBETWEEN A 60% & A 67% BREAK INTERVAL. THIS IS DUE TO THE FACT THAT MANYFOREIGN NATIOS USE A 67% BREAK INTERVAL.

HAVE YOU EVER BEEN IN AN OFFICE OR A SIMILAR FACILITY AND SAW A FONE WAITINGTO BE USED FOR A FREE CALL BUT SOME ASSHOLE PUT A LOCK ON IT TO PREVENTOUTGOING CALLS?

WELL, DON'T FRET PHELLOW PHREAKS, YOU CAN SIMULATE PULSE DIALING BY RAPIDLYDEPRESSING THE SWITCHOOK. (IF YOU DEPRESS IT FOR LONGER THAN A SECOND ITWILL BE CONSTRUED AS A DISCONNECT.) BY RAPIDLY SWITCHOOKING YOU ARE CAUSINGTHE LOCAL LOOP TO BE BROKEN & MADE SIMILAR TO ROTARY DIALING! THUS IF YOUCAN MANAGE TO SWITCHOOK RAPIDLY 10 TIMES YOU CAN REACH AN OPERATOR TO PLACEANY CALL YOU WANT! THIS TAKES ALOT OF PRACTICE, THOUGH. YOU MIGHT WANT TOPRACTICE ON YOUR OWN FONE DIALIN A FRIEND'S # OR SOMETHING ELSE. INCIDENTALLY, THIS METHOD WILL ALSO WORK WITH DTMF FONES SINCE ALL DTMF LINESCAN ALSO HANDLE ROTARY.

ANOTHER PROBLEM WITH PULSE DIALING IS THAT IT PRODUCES HIGH-VOLTAGE SPIKESTHAT MAKE LOUD NOISES IN THE EARPIECE AND CAUSE THE BELL TO "TINKLE." IF YOUNEVER NOTICED THIS THEN YOUR FONE HAS A SPECIAL "ANTI-TINKLE" & EARPIECESHORTING CIRCUIT (MOST DO). IF YOU HAVE EVER DISSECTED A ROTARY FONE (A MUSTFOR ANY SERIOUS PHREAK) YO WOULD HAVE NOTICED THAT THERE ARE 2 SETS OFCONTACT THAT OPEN AND CLOSE DURING PULSING (ON THE BACK OF THE ROTARY DIALUNDER THE PLASTIC COVER). ONE OF THESE ACTUALLY OPENS AND CLOES THE LOOPWHILE THE OTHER MUTES THE EARPIECE BY SHORTING IT OUT. THE SECOND CONTACTSALSO ACTIVATES A SPECIAL ANTI-TINKLE CIRCUIT THAT PUTS A 340 OHM RESISTORACROSS THE RINGING CIRCUIT WHICH PREVENTS THE HIGH VOLTAGE SPIKES FROMINTERFERRING WITH THE BELL.

DUAL TONE MULTI FREQUENCY (DTMF) IS A MODERN DAY IMPROVEMENT ON PULSE DIALINGIN SEVERAL WAYS. FIRST OF ALL, IT IS MORE CONVENIENT FOR THE USER SINCE ITIS FASTER AND CAN BE USED FOR SIGNALING AFTER THE CALL IS COMPLETED (IE,SCC'S, COMPUTERS, ETC.). ALSO, IT IS MORE UPTO PAR WITH MODERN DAY SWITCHINGEQUIPMENT (SUCH AS ESS) SINCE PULSE DIALING WAS DESIGNED TO ACTUALLY MOVERELAYS BY THE NUMBER OF DIGITS DIALED (IN SXS OFFICES).

EACH KEY ON A DTMF KEYPAD PRODUCES 2 FREQUENCIES SIMULTANEOUSLY (ONE FROM THEHIGH GROUP AND ANOTHGR FROM THE LOW GROUP).

THE FOURTH COLUMN (1633 HZ) IS NOT NORMALLY FOUND O REGULAR FONES BUT IT DOESHAVE SEVERAL SPECIAL USES. FOR ONE, IT IS USED TO DESIGNATE THE PRIORITY OFCALLS ON AUTOVON, THE MILITARY FONE NETWORK. THESE KEY ARE CALLED: FLASH,IMMEDIATE, PRIORITY, & ROUTINE (WITH VARIATIONS) INSTEAD OF ABCD. SECONDLY,THESE KEYS ARE USED FOR TESTING PURPOSES BY THE TELCO. IN SOME AREA YOU CANFIND LOOPS AS WELL AS OTHER NEAT TESTS (SEE PART II) ON THE 555-1212DIRECTORY ASSISTANCE EXCHANGE. FOR THIS, YOU WOULD CALL UP AN DA IN CERTAINAREAS [THAT HAVE AN AUTOMATIC CALL DISTRIBUTOR (ACD)] AND HOLD DOWN THE "D"KEY WHICH SHOULD BLOW THE OPERATOR OFF. YOU WILL THEN HEAR A PULSING DIALTONE WHICH INDICATES THAT YOU ARE IN THE ACD INTERNAL TESTING MODE. YOU CANGET ON ONE SIDE OF A LOOP BY DIALING A 6. THE OTHER SIDE IS 7. SOME PHREAKSCLAIM THAT IF THE PERSON ON SIDE 6 HANGS UP, OCCASIONALLY THE EQUIPMENT WILLSCREW UP AD START DIRECTING DIRECTORY ASSISTANCE CALLS TO THE OTHER SIDE OFTHE LOOP. ANOTHER ALLEGED TEST IS CALLED REMOB WHICH ALLOWS YOU TO TAP INTOLINES BY ENTERING A SPECIAL CODE FOLLOWED BY THE 7 DIGIT NUMBER YOU WANT TOMONITOR. THEN THERE IS THE POSSIBILITY OF MASS CONFERENCING.

ACD'S ARE BECOME RARE THOUGH. YOU WILL PROBABLY HAVE TO MAKE SEVERAL NPA-555-1212 CALLS BEFORE YOU FIND ONE.

YOU CAN MODIFY REGULAR FONES QUITE READILY SO THAT THEY HAVE A SWITCH TOCHANGE BETWEEN THE 3RD AND 4TH COLUMNS. THIS IS CALLED A SILVER BOX (AKAGREY BOX) AD PLANS CAN BE FOUND IN TAP AS WELL AS ON MANY BBS'S.

TRANSMITTER/RECEIVER:---------------------

WHEN YOU TALK INTO THE TRANSMITTER, THE SOUND WAVES FROM YOUR VOICE CAUSE ADIAPHRAGM TO VIBRATE AND PRESS AGAINST THE CARBON GRANULES (OR ANOTHERSIMILAR SUBSTANCE). THIS CAUSES THE CARBON GRANULES TO COMPRESS AND CONTRACTTHUS CHANGING THE RESISTANCE OF THE DC CURRENT FLOWING THROUGH IT. THEREFORE, YOUR AC VOICE SIGNAL IS SUPERIMPOSED OVER THE DC CURRENT OF THE LOCAL LOOP. THE RECEIVER WORKS IN A SIMILAR FASHION WHERE THE SIMPLE TYPES UTILIZE AMAGNET, ARMATURE, & DIAPHRAGM.

HYBRID/INDUCTION COIL:----------------------

AS YOU MAY HAVE NOTICED, THERE ARE TWO WIRES FOR THE RECEIVER AND TWO FOR THETRANSMITTER IN THE FONE, YET THE LOCAL LOOP CONSISTS OF 2 WIRES INSTEAD OF 4. THIS 4-WIRE TO 2-WIRE CONVERSION IS DONE INSIDE THE FONE BY A DEVICE KNOWNAS AN INDUCTION COIL WHICH USES COUPLING TRANSFORMERS.

THE REASON 2 SIRES ARE USED ON THE LOCAL LOOPS ARE BECAUSE IT IS ALOT CHEAPERFOR THE TELCO. ALTHOUGH, ALL OF THE INTER-OFFICE TRUNKS UTILIZE 4 WIRES. THIS IS NECESSARY FOR FULL DUPLEX (IE, SIMULTANEOUS CONVERSATION ON BOTHSIDES) AND FOR AMPLIFICATION DEVICES. THERE ARE SIMILAR DEVICES IN THE CO'S,KNOWN AS A HYBRID, THAT COUPLE THE 4-WIRE TRUNKS TO THE 2-WIRE LOCAL LOOPSAND VISA-VERSA.

MISCELLANEOUS:--------------

IN THE TELEPHONE, THERE IS ALSO A BALANCING NETWORK CONSISTING OF A FEWCAPACITORS & RESISTORS WHICH PROVIDE SIDETONE. SIDETONE ALLOWS THE CALLER TOHEAR HIS OWN VOLUME IN THE RECEIVER. HE CAN THEN ADJUST HIS VOICEACCORDINGLY. THIS PREVENTS PEOPLE FROM SHOUTING OR SPEAKING TOO SOFTLYWITHOUT NOTICING IT.

HOLD:

WHEN A TELEPHONE GOES OFF HOOK, THE RESISTANCE DROPS BELOW 2500 OHMS. ATTHIS POINT, THE TELCO WILL SEND A DIAL TONE. TO PUT SOMEONE ON HOLD YOU MSTPUT A 1000 OHM RESISTOR (1 WATT) ACROS THE TIP & RING BEFORE IT REACHES THESWITCHOOK. IN THIS WAY, WHEN THE FONE IS HUNG UP (FOR HOLD) THE RESISTANCEREMAINS BELOW 2500 OHMS WHICH CAUSES THE CO TO BELIEVE THAT YOU ARE STILL OFF-HOOK.